Washington: As the Congress took steps to accelerate the voting process on the resolution to authorise military action against the Assad regime, US Secretary of State John Kerry said that inaction in Syria would empower the extremist groups.

"I guarantee you if we turn our backs today, the picture we all saw in the media of people being shot, will be seen more because extremists will be attracted to this and they will be funded as the only alternative to take on Assad," said Kerry yesterday.

Kerry said if the United States does not act, Americans will see more videos such as the one aired by The New York Times yesterday that purports to show Islamists executing seven captured Syrian soldiers.

"In fact, I believe those men in these videos will be disadvantaged by an American action to the chemical weapons used because it, in fact, empowers the moderate opposition," Kerry added.

The Secretary of State said there are fewer than a dozen `really bad` opposition groups - "jihadists" - who have been attracted to the chaos in Syria.

"The US is dead-set against providing them support. They are not part of the opposition that is being supported by our friends and ourselves. We support a moderate opposition which condemned what has happened today," he told the MSNBC news.

Kerry insisted that the US military strike is intended only as a warning to Assad that he would be punished for any further use of chemical weapons and was not meant to tip the balance of the civil war to the rebels and drive Assad from office.

"We`re not remotely talking about getting America involved directly between any of those forces," he said, adding Assad`s departure, and who takes over from him in a transitional government, must be negotiated.

Kerry said that if Congress does not authorise a strike, it will be sending Assad a message that he can use chemical weapons against his own people with impunity.